Process for producing certain oxi



Patented Dec. 31, 1935 PROCESS FOR PRODUCING oER'rAiNoxI- DATION PRODUCTS-F CASTOR OIL AND THE LIKE Melvin D,c Groote, St. Louis, and Bernhard Keiser, Webster Groves, Mo., assignors to Tretolite Company, Webster Groves, Mo., a corporatlon of Missouri No Drawing. Application January 30, 1935, Serial No. 4,091

'1 Claims.

This invention relates to the manufacture of certain oxidation products of castor oil and the like, i. e., products obtained'or produced by the oxidation of castor oilor castor oil bodies at a relatively low temperature and at a pressure of not over 125 lbs.

The obect of our invention is to provide a novel process for producing products or materials ofthe kind mentioned. Briefly described, our process consists in-subjecting castor oil or the like to pressure oxidation in the presence of an autooxidizer-catalyst consistingof a pinene body.

In order to clearly define and explain our invention, it will be necessary to refer brieflyto prior processes or procedures that have been employed or suggested to obtain products or materials produced by the oxidation or blowing ,of various oils with dry or moist air or oxygen. In a general way, animal or vegetable oils may be divided into five general classes, based on their susceptibility to oxidation reactions, involving the use of air or oxygen. The first of the above-mentioned classes includes such materials as stearic acid, which does not contain an ethylene linkage and 5 is not saturated. Such a fatty body is not susceptible to oxidation by the conventional methd l he second of the above-mentioned classes isunique, in that the only material or materials of 30 said class that are commercially available, are castor oil and simpe castor oil derivatives, such as ricinoleic acid, or poly-ricinoleic acid. Castor oil is characterized by the fact that it may be exposed to air or oxygen for a long time in a very 35 thin film, without absorbing any oxygen. In other words, notwithstanding the fact that castor oil contains an ethylene linkage, still, so far as reactions at ordinary temperatures or pressures are concerned, it is hardly more reactive towards 40 air or oxygen than if it were a saturated fatty body, such as stearin, or stearic acid.

The third of the above-mentioned classes of materials includes the so-called non-drying oils. These oils, such as oleic acid, olein, etc., are non- 45 drying in the sense that they do not absorb oxygen and dry quickly enough to produce a paint film. However, they are differentiated from castor oil, in that a film exposed to air or oxygen at ordinary temperatures for a period of time, '50 will oxidize slowly but rather completely.

' The fourth of the above-mentioned classes of materials consists of the so-called semi-drying oils, such as cotton seed oil, and certain marine oils which are more reactive than oleic acid or 55 the like, but not so reactive as the true drying oils,

which are characterized; for example, by linseed oil.

The fifth of the above-mentioned classes of materials comprises the true drying oils which absorb air or oxygen rapidly enough to produce vl'i a paint film when exposed in a thin layer and which may absorb oxygen rapidly enough at ordinary temperatures to-cause spontaneous combustion.

It is common practice to blow or oxidize va- 10 rious fatty materials of the kind above enumerated to produce materials intended for use in various arts. Linseed oil, for example, is oxidized toproduce a solid, such as linoxyn. Certain oils areoxidized to produce plasticizers for 15 use in the manufacture of artificial leather and the like. Certain oils are oxidized, so as to give miscibility with petroleum oils to produce blended lubricating oils. Certain oils are oxidized to produce a product of certain desired character- 20 istics employed in the manufacture of varnish and the like.

- It is well known that an oxidation process or procedure,'which may be suitable for one of the five general classes of oils, previously mentioned, may not be suitable for a different class. For example, the process used to oxidize the linseed oil type of oil are usually ineffective in regard to castor. oil, or even in regard to oleic acid and the processes employed for oxid.izing olive oil or rape seed oil, may be entirely too drastic for use on linseed oil. Moreover, in the oxidation of oils, particularly linseed oil, and certain marine oils, the resultant product depends entirely on the mode of treatment. Marine oils, for example, may be oxidized primarily, to decolorize or de-odorize the oil, and such oxidation is intended solely to oxidize or destroy the impurities so as to permit the oil under treatment to remain more or less unchanged.

In the co-pending application for patent of the present applicants jointly with Arthur F. Wirtel, Serial No. 752,718, filed November 12, 1934, there is disclosed a process for producing blown oils, that involves subjecting fatty bodies to oxidation after admixture with a relatively small amount of a vegetable oil of the true drying type,

with or without a small amount of a fat splitting sulfonic acid. i

In another co-pending application for patent filed by the above--mentioned applicants, Serial No. 760,031, filed December 31, 1934, there is disclosed a procession producing poly keto fatty bodies or poly aldehydic fatty bodies, that involves the oxidation of castor oil, polyricinoleic or rlcinoleic acid under pressure at a relatively low temperature. The temperature employed in the said process is below the temperature at which castor oil can be oxidized under ordinary conditions, for instance, it is less than 150 C., and generally speaking, the oxidation is conducted at approximately 120 C. The pressure employed in the said process varies from 25 to 125 lbs. gauge pressure, the pressure most conveniently employed being about 45 lbs. In the abovementioned low-temperature-low-pressure process, the reaction takes place primarily, due to the presence of a catalyst, which consists of a true drying oil, such as linseed oil. Usually, the castor oil body, before being subjected to low temperature pressure oxidation, is mixed with not over 20% of linseed oil. In the absence of linseed oil, either the reaction does not take place, or the reaction takes place so slowly that such oxidation procedure would not be feasible or economical, or might even produce some other compound. In a general way, oxidation of a mixture of 90% castor oil and 10% of linseed oil takes place very readily at a temperature of 120 C. and 45 lbs. air pressure. Such reaction may be completed'in ten hours or less, depending upon the size of pressurevessel used'during oxidation. The air, employed may be dried or moist, in the sense that it may carry its normal moisture content.

Castor oil is diiferentiated from other oils and other fatty materials in regard to its reaction towards oxidation in various manners. As has been previously pointed out, castor oil, although containing an ethylene linkage, does not oxidize under ordinary conditions, even after long exposure in a thin film. For this reason it is even less reactive than'ordinary so-called nondrying oils. Its action is more analogous, so far as oxidation goes, to inert oils of the stearic acid type. Castor oil orricinoleic acid or the related esters, such as the ethyl, methyl, propyl, or butyl ester, are further distinguished by the fact that the materials contain an alcoholiform hydroxyl, and thus, ricinoleic acid is not only a fatty acid, but is also a fatty alcohol and is more properly described, perhaps, as an alcohol acid. Such materials which are characterized by the presence of a 'ricinoleic acid radical will be referred to as castor oil bodies because they are invariably derived from castor oil as an original raw material. It is a secondary alcohol, and as is well known, the oxidation of a secondary alcohol produces a ketone, and thus, it is believed that the cautious oxidation of castor oil in the manner described in the said De Groote et al.

application Serial No. 760,031, results in the formation of keto acids or keto acid bodies, and

. particularly, in the formation of poly keto acid 46 and 47), it issufficient to state that an auto oxidizer, in a general manner, oxidizes in proportion to its own mass, and it does not emerge unchanged from the reaction which it has caused.

On the other hand, the addition of linseed oil, for example, to castor oil, does not hasten the reaction directly in proportion to the added linseed oil. For instance, an -20 mixture does not necessarily oxidize twice as rapidly as a -10 mixture. Furthermore, it is well known that some auto-oxidizers may be entirely regenerated and again serve as a carrier of free oxygen to the oxidizable substance. It is further possible that the oxidation of linseed oil or any other added material may result in certain new prod ucts, which, in turn, may act as auto-oxidizers or as oxidation catalysts. Accordingly, in the said De Groote et al.. application Serial No. 760,031, the linseed oil used in the process is referred to as an auto-oxidizer catalyst; with the understanding that the reaction may be promoted by the linseed oil or some product therefrom acting either in the capacity of an autooxidizer or in the capacity of an oxidation catalyst, or in a dual capacity. As far as the commercial operation of such oxidation reactions are concerned, it is obvious that these materials may be added inthe designated proportion and the mixture submitted to oxidation under the described conditions, so as to obtain the advantages described, without reference as to the theoretical aspects of the oxidation step itself.

We have found that while certain materials will act as auto-oxidizer-catalysts, so as to promote the cautious and controlled oxidation of castor oil or the like at relatively low temperatures and under moderate pressures of the kind described, there does' not appear to be any general characteristic whereby this particular property of a substance may be anticipated. Materials which may serve as auto-oxidizers or catalysts in regard to other reactions may not have any effect in hastening the oxidation of castor oil under the described conditions. Likewise, materials which may be effective in hastening the oxidation of castor oil, under the conditions described, may not be effective in other reactions where it is known that some other auto-oxidizercatalysts may be employed. At least, at the present time and in regard to the low temperature pressure oxidation of castor oil bodies, it appears that this peculiar property is that of an. individual substance or compound, and cannot be ascribed to a class broadly, as far as we are now aware.

We have also found that a pinene body is a very effective auto-oxidizer-catalyst when employed in a low temperature pressure oxidation of castor oil bodies. Pinene bodies are bodies which have the typical internal bridge structure of pinene together with the single unsaturated bond which characterizes pinene. The formula of pinene is as follows: (see page 627 of the publication Text Book of Organic Chemistry, Bernthsen, 1931 edition).

Pinene urated bond. Ordinarily speaking, alpha pinene is so readily available as the chief constitutent of Americanoil of turpentine that there is no benefit to be derived by using some other pinene body, because invariably, with the possible exception of beta pinene, which occurs in some foreign turpentine, the other members of the class of materials referred to as pinene bodies, are invariably more expensive and do not appear to ofier any added advantage over the lower priced and more readily available alpha pinene. Polymerized pinene, sold in the trade as fat oil may be used. This is also true of camphene, which is structurally similar to pinene. In the actual oxidation process itself we prefer to use American oil of turpentine, which represents a semi-pure form of alpha pinene. In our process we use not over 20%, and preferably, approximately 10% of domestic turpentine in the low temperature pressure oxidation of castor oil, so as to produce oxidation products of the kind which appear to be poly keto or poly aldehydo fatty bodies. We prefer that the oxidation be conducted with air having its ordinary moisture content and at a temperature of 120 C. and at a pressure of 45 lbs.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A process which consists in substantially oxidizing castor oil by means of air of normal moisture content at a temperature within the range of approximately 120 C. to 150 C. and at a gauge pressure within the range of 25 lbs. to 125 lbs., and using 10% to 20%, by weight of alpha pinene as an auto-oxidizer-catalyst.

2. A process which consists in substantially oxidizing castoroil by means of air of normal moisture content at a temperature within the range of approximately 120 C. to 150 C. and at, a gauge pressure within the range of 25 lbs. to 125 lbs., and using 10% to 20%, by weight of alpha pinene, in the form of American oil of turpentine, as an auto-oxidizer-catalyst.

3. A process for the purpose described, which consists in substantially oxidizing castor oil by means of air of normal moisture content at a 5 temperature of approximately 120 C..and under a gauge pressure of 45 lbs., and using as anautooxidizer-catalyst, American oil of turpentine, equivalent in weight to 10% of the castor 011 being oxidized. 10

4. A process for the purpose described, characterized by substantially oxidizing, by means of a gaseous, oxygen-containing medium, a castor oil body at a temperature within the range of approximately 120 C. to 150 C. and at a gauge 15 pressure within the range of 25 lbs. to 125 lbs., and using 10% to 20%, by weight, of an unsaturated pinene body as an auto-oxidizer-catalyst, said castor all body being characterized by the presence of a ricinoleic acid radical. 20 s 10% to 20%, by weight, of an unsaturated pinene body as an auto-oxidizer-catalyst.

6. A process for the purpose described, characterized by substantially oxidizing, by means of 30 a gaseous, oxygen-containing medium, castor oil at a temperature within the range of approximately 120 C. to 150 C. and at a gauge pressure within the range of 25 lbs. to 125 lbs., and using 10% to 20%, by weight, of alpha pinene as an auto-oxidizer-catalyst.

'7. A process for the purpose described, characterizedvby substantially oxidizing castor oil, by means of a gaseous, oxygen-containing medium, at a temperature within the range of approxi- 40 mately C. to 150 C. and at a gauge pressure within the range of '25 lbs. to lbs., and using 10% to 20% by weight, of alpha pinene, in the form of American oil of turpentine, as an autooxidizer-catalyst. 45

l I MELVIN DE GROOTE.

BERNHARDiKEISE-R. 

